System for progressive shutdown of cooling water sprays



1968 .1. R. TISKUS ETAL 3,417,810

SYSTEM FOR PROGRESSIVE SHUTDOWN OF COOLING WATER SPRAYS Filed Sept. 1,1965 ULSE SOURCE INVENTORS JOHN R. nsxus BY REGIS A. VEY

ATTORNEY United States Patent 3,417,810 SYSTEM FOR PROGRESSIVE SHUTDOWN0F COOLING WATER SPRAYS John R. Tiskus, Monroeville Borough, and RegisA. Vey,

Ben Avon, Pa., assignors to United States Steel Corporation, acorporation of Delaware Filed Sept. 1, 1965, Ser. No. 484,398 5 Claims.(Cl. 164150) ABSTRACT OF THE DISCLOSURE A system for progressivelyclosing the valves controlling the water supply to cooling nozzles, asthe trailing end of a casting travels down between banks of guiderollers, includes a counter set in operation at a predetermined time andactuated by successive pulses, one for each increment of travel of thecasting. After a predetermined number has been accumulated by thecounter, it notches forward a sequence switch one step and resets itselfto zero for a repeat operation. The sequence switch operates valveactuators to close the valves successively.

This invention relates to continuous casting apparatus in which a steelslab is progressively cooled by means of a plurality of verticallyspaced water sprays as it descends below the mold, and more particularlyto an apparatus for shutting down these sprays in succession as the tailend of the casting passes therebelow.

In the continuous casting of metals and alloys such as steel, thecasting is continuously formed in an openended tubular water-cooledflow-through mold which constitutes the primary cooling zone. After themold has been initially filled and a thin shell of solid metal has beenformed adjacent the mold walls and the top of the starter bar, thecasting is allowed to descend below the mold through a secondary coolingzone consisting of a plurality of vertically spaced guide rolls andvertically spaced sprays which direct cooling water against the opposedfaces of the casting. The speed of descent of the casting is controlledby means of motor driven pinch rolls located below the secondary coolingsection.

When a casting is completed, it is necessary to shut down each of thewater sprays in sequence as the tail end of the casting descends below apreselected position relative to said spray, in order to preventovercooling of the tail end of the casting. Overcooling would makesubsequent manipulation such as bending and rolling extremely difiicult,and would produce cracks and strains due to cold working of the metal.

The primary object of this invention is to provide an apparatus whichwill shut down each of the water nozzles in the secondary cooling zoneof a continuous casting apparatus in sequence as the tail end of thecasting descends below a preselected position relative to said nozzle,so that the tail end of the casting is not overcooled.

The apparatus of this invention includes an open-ended tubularWater-cooled continuous casting mold in which a casting may be formed,motor-driven pinch rolls below the mold for controlling the speed ofdescent of the casting, and a plurality of vertically spaced watersprays between the mold and the pinch rolls for directing cooling wateragainst the casting. Valves and valve actuators therefor are providedfor shutting off the water supply to the nozzle, as well as signal ofmeasuring means for indicating the position of the tail end of thecasting as it descends below the mold, and control means responsive tothe signal means for operating the valve actuators to shut oil the watersupply to each of the cooling water nozzles in sequence, beginning atthe top of the cooling section, as the tail end of the casting descendsbelow the mold. In a preferred embodiment of this invention,

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the signal or measuring means comprises a pulse counter driven by thepinch rolls, which sends out pulses whose number is directlyproportional to the number of revolutions of the pinch rolls and henceto the distance the casting descends, and a reset counter which countsthe number of pulses and sends out a pulse current to a controller whena predetermined count has been reached. The control means for shuttingoff the water supply may include a drum controller which is programmedto close nozzle valves in sequence, and cam followers and switchescontrolled by the drum controller for actuating the control valvesprovided on the water nozzles.

In the drawings, the single figure is a schematic diagram of theapparatus for shutting oiT the water supply to each of the water spraysin the secondary cooling zone as the tail end of the casting descendstherebelow.

Referring now to the drawing, the apparatus of this invention comprisesan open-ended tubular water-cooled flow-through continuous casting mold10 in which a steel casting 11 is formed, a secondary cooling zone belowthe mold, generally indicated at 12, comprising a plurality of guiderollers 13 for contacting the two opposed faces of the casting, and aplurality of vertically spaced Water pipes 20 to 29 inclusive, eachincluding a terminal spray nozzle which is adapted to direct coolingwater against the adjacent face of the casting. Generally a horizontalrow of nozzles is provided on each side of the casting line at eachelevation spaced across the casting width. The vertical distance betweenadjacent rows of nozzles is constant throughout the secondary coolingzone 12. In this case each numeral 20 to 29 represents a row of nozzles.The speed of descent of the casting is controlled by means of motordriven pinch rolls 30 located below the secondary cooling zone. Thecasting 11 is shown herein at the completion of a casting operation,after mold 10 has been emptied and when the tail end of the casting isin the secondary cooling zone.

The water supply to the nozzles 20 to 29 inclusive is controlled byvalves 40 to 49 inclusive. Where a row of nozzles is provided at eachelevation, a single valve may control the water supply to the entirerow. The opening and closing of valves 40 to 49 inclusive is controlledby valve actuators 50 to 59 inclusive, respectively. Valves 40 to 49 maybe of the simple on-off variety, in which case actuators 50 to 59 aresolenoids. Where more precise control of the water flow rate to eachnozzle is desired, valves 40 to 49 may be of the variable opening type,and actuators 50 to 59 are electric motors which can set the respectivevalves at any position from shut to full open.

The system for controlling the shutoff of water to nozbles 20 to 29inclusive includes measuring means which provides a signal indicatingthe position of the tail end of the casting, control means responsive tothe signal means for sequentially operating the valve actuators 50 to 59inclusive to shut off the water supply to each of the nozzles 20 to 29in sequence as the tail end of the casting descends below a preselectedposition with respect to that nozzle, and activator means formaintaining the control means in an inactive state while a casting isbeing formed in the mold and for activating the signal means and thecontrol means when the tail end of the casting descends below the mold.

The signal or measuring means includes a pulse source 60 which isactivated by a rotating permanent magnet 61 driven by pinch rolls 30 sothat the number of pulses sent out is directly proportional to thenumber of revolutions of the pinch rolls 30 and hence the distancetraveled by casting 11. The signal means also includes a reset counter62 which counts pulses from source 60 until a predetermined number isreached and then sends out a secondary pulse or signal current andresets itself to zero.

The control means includes a rotating programmed drum controller 63which is adapted to be rotated through a fixed predetermined are everytime it receives a pulse or signal current from reset counter 62, aplurality of cam followers 70 to 79 inclusive adapted to ride on thesurface of said drum controller 63 and to be actuated by programmedsurface irregularities 011 the drum controller, and a plurality ofnormally open microswitches 80 to 89 which are closed by actuation ofthe respective cam followers 70 to 79 inclusive. Closure ofmicroswitches 80 to 89 causes the respective valve actuators 50 to 59 tobe operated to close valves 40 to 49 and thereby shut down the watersupplies to nozzles 20 to 29 in sequence as the tail end of the castingdescends.

The activator means includes push button switch 90 by which operation ofthe signal and control means is initiated, and the relays 91 and 92 forcontrolling current to reset counter 62 and drum controller 63.

The pulse source 60 may be any conventional device for generatingelectrical impulses. A vibrating reed switch encolsed in a suitablecasing, such as an RCA Minireed Switch, type RE2100, is an example.

The reset counter may be any device which is capable of receiving pulsesfrom the pulse source 60 and causing activation of a controller when apredetermined number of pulses has been received. This reset countermust be able to reset itself to zero and begin a new count of pulsessimultaneously with activation of the controller. The reset counter 62is preset for a pulse count such that the tail end of the casting 11descends by a distance equal to the vertical distance between adjacentsprays (or rows of sprays) 20 to 29 between successive secondary pulsessent out by the counter. One suitable reset counter is Model HZl50A6,manufactured by Eagle Signal Company and described in its Bulletin 725.

The rotating drum controller 63 includes a plurality of slots 64arranged in rows, each of said slots being adapted to receive a peg 65which will activate a cam follower. By placing the pegs 65 in thedesired slots and using a plurality of cam followers 70 to 79 inclusive,one for each row of slots in drum controller 63, any desired program orsequence of operations of the switches controlled by the cam followersmay be established. Each pulse from reset counter 62 advances drumcontroller 63 one step, actuating the next cam follower in the series 70to 79. Drum controllers of this type are known in the art. One suitablecontroller is Tenor Model 30, manufactured by The Tenor Company, Butler,Wis., and described in its Bulletin 0363.

The apparatus for shutting down nozzles 20 to 29 should he set in motiononly after the tail end of casting 11 has descended below mold intosecondary cooling zone 12. This causes each nozzle 20 to 29 inclusive(or each horizontal row of nozzles at a given elevation) to be shut downin sequence, as the tail end of the casting descends below thepreselected position relative to that nozzle. For this reason the systemof this invention must be placed in operation at the correct time sothat the water nozzles 29 are shut down neither prematurely nor toolate.

A push button switch 90 under the control of an operator who is in aposition Where he can see the tail end of casting 11 descending belowmold 10 is provided for activating the shutdown system of thisinvention.

Closure of switch 90 energizes relay 91, which remains energized bymeans of holding contact 91a. Normally open contact, contact 9111 alsocloses when relay 91 is energized thereby supplying power to pulsesource 60 and reset counter 62.

Lines 97 and 98 alternatively connect reset counter 62 to the same sideof an AC power line 100. Line 98 includes relay 92. Normally the circuitfrom counter 62 back to the power line 100 runs through line 97. Aninternal switching arrangement in reset counter 62 switches the currentfrom line 97 to line 98 when the predetermined count is reached,energizing relay 92. Relay 92 when energized closes contact 92a tosupply power to step the drum controller 63.

-When the casting operation is ended and the tail end of the castingdescends below mold 10 into secondary cooling zone 12, the apparatus ofthis invention is put into operation, by closing button switch 90. Thiscloses circuit 96 so that pulses emitted by source 60 are transmitted toreset counter 62. Reset counter 62 is programmed in advance to actuatecontroller 63 and reset itself to zero when it receives the number ofpulses emitted during the descent of the tail end of casting '11 fromone row of sprays to the next row. When this count is reached, drumcontroller 63 is advanced one step. This advancement causes a camfollower controlling mioroswitch to be triggered by a peg in drumcontroller 63. When this cam follower is triggered, microswitch 80' isclosed, energizing valve controller 50 which causes valve 40 to be shutdown. This cuts ofl the water supply to nozzle 20. Drum controller 63then stands motionless until the predetermined count is reached again.Then drum controller 63 is again advanced one step, this time causingmicroswitch 81 to be closed by a mechanism similar to that for closingmicroswitch 80, and thereby shutting off the water supply to nozzle 21.In this manner each of the water nozzles 20 to 29 is shut down insuccession as the tail end of the casting descends below the elevationat which that nozzle is located. 1

What is claimed is:

1. In a continuous casting apparatus comprising an open-ended tubularmold for producing a metal casting,

pinch rolls below said mold for controlling the rate of' descent of saidcasting, a plurality of vertically spaced nozzles below said mold fordirecting cooling water against said casting as it descends, and valvesand actuators therefor for individually controlling the water supply toeach of said nozzles, the combination therewith of means for shuttingoff the water supply to each of said nozzles in sequences as the tailend of the casting descends below a preselected position relative tosaid nozzle, said means comprising:

signal means to provide a signal indicating the position of the tail endof said casting as it descends below the mold, and

control means responsive to said signal means for sequentially operatingsaid actuators to shut otf the water supply to each of said nozzles insequence as the tail end of said casting descends below said preselectedposition, said signal means including a pulse source adapted to emit anumber of pulses proportional to the distance through which the tail endof said casting descends and a reset counter adapted to count saidpulses and to send out a secondary pulse current and simultaneouslyreset itself to zero when a predetermined count is reached.

2. In a continuous casting apparatus comprising an open-ended tubularmold for producing a metal casting, pinch rolls below said mold forcontrolling the rate of descent of said casting, a plurality ofvertically spaced nozzles below said mold for directing cooling wateragainst said casting as it descends, and valves and actuators thereforfor individually controlling the water supply to each of said nozzles,the combination therewith of means for shutting off the water supply toeach of said nozzles in sequence as the tail end of the casting descendsbelow a preselected position relative to said nozzle, said meanscomprising:

signal means to provide a signal indicating the position of the tail endof said casting as it descends below the mold, and

control means responsive to said signal means for sequentially operatingsaid actuators to shut off water supply to each of said nozzles insequence as the tail end of said casting descends below said preselectedposition, said control means including a drum controller adapted to berotated by a predetermined fixed amount on receipt of a signal from saidsignal means, cam follower means adapted to ride on the surface of saiddrum controller, said drum controller having means for actuating saidcam follower means, and a plurality of switches adapted to be closed byactuation of said cam follower means to operate said valve actuators andthereby close said valves controlling said water sprays.

3. In a continuous casting apparatus comprising an open-ended tubularmold for producing a metal castingpinch rolls below said mold forcontrolling the rate of descent of said casting, a plurality ofvertically spaced nozzles below said mold for directing cooling wateragainst said casting as it: descends, and valves and actuators thereforfor individually controlling the water supply to each of said nozzles,the combination therewith of means for shutting off the water supply toeach of said nozzles in sequence as the tail end of the casting descendsbelow a preselected position relative to said nozzle, said meanscomprising:

means for measuring the distance traveled by the casting after thetail-end thereof has reached a predetermined point which emits a signalfor each unit of travel of said casting, means adapted to accumulatesignals from said measuring means and control means responsive to saidaccumulator means for sequentially operating said actuators to shut 01fthe water supply to each of said nomles in sequence as the tail end ofsaid casting descends below said preselected position.

4. Apparatus according to claim 3 including means for maintaining saidmeasuring means and said control means in an inactive state until thetail end of the casting descends below the mold, actuation of saidmaintaining means rendering operative said measuring means and saidcontrol means to cause sequential shutting down of the water supplies tosaid nozzles.

5. The combination with a continuous-casting apparatus comprising anopen-ended tubular mold, pinch rolls below said mold for controlling therate of descent of said casting, a plurality of vertically spacednozzles below said mold for directing cooling water against said castingas it descends, valves and actautors therefor for individuallycontrolling the water supply to each of said nozzles, of means forshutting off the water supply to each of said nozzles in sequence as thetail end of the casting descends below a preselected position relativeto said nozzle, said means comprising:

a pulse source actuated according to the descent of the casting, acounter connected to count said pulses and adapted to send out asecondary pulse and reset itself to zero when a predetermined count isreached,

a drum controller adapted to be moved by a fixed predetermined amount onreceipt of one of said secondary pulses, said controller having asurface to cause sequential shutdown of the water supplies to saidsprays, and

cam follower means adapted to be actuated by said surface to actuate aswitch causing shutdown of the water supply to each of said nozzles insequence.

References Cited UNITED STATES PATENTS 1,444,862 2/1923 Anderson 62157X2,206,930 7/1940 Webster 164l55 2,332,759 10/1943 Schwarz 164-872,453,527 11/1948 Mero 118--2 2,804,665 9/1957 Harter et a1. 164-1343,040,399 6/1962 Rafiaelli 164-157 3,283,370 11/1966 Jendraszkiewicz164-154 3,364,977 1/1968 Machida 164--l54 X 3,358,743 12/1967 Adams164-154 3,356,061 12/1967 Wiggins 118-2 FOREIGN PATENTS 467,475 6/ 1937Great Britain.

I. SPENCER OV'ERHOLSER, Primary Examiner.

R. S. ANN-EAR, Assistant Examiner.

US. Cl. X.R.

6223l; ll88; 13457, 122; 164l54, 157

